The present disclosure relates to semiconductor packages and, more particularly, to a semiconductor package with a PoP structure and a refresh control method thereof.
A dynamic random access memory (DRAM) may be used as a main memory of an application processor (hereinafter referred to as “AP”) or a central processing unit (CPU).
There is an increasing demand for lower power consumption in a mobile DRAM for use in a mobile device such as a smartphone.
Since a DRAM is characterized in that charges charged to a storage capacitor constituting a memory cell leak with the passage of time, the DRAM periodically requires a refresh operation to recharge the charges within a certain time.
Power consumed for a refresh operation of a DRAM is one of the parts of power consumed in the DRAM. One of the ways to reduce power consumed for a refresh operation is to extend a period of the refresh operation. The frequency of the refresh operation is proportional to the amount of leakage current at a storage capacitor constituting a DRAM memory cell and is exponentially proportional to operation temperature. As a result, larger the amount of the leakage current and the higher the operation temperature, the more frequently the refresh operation must be performed.
Along with the request for higher performance of state-of-the-art mobile devices, the stacking technology of semiconductor chips and the stacking technology of semiconductor packages have been developed.